“Raising taxes won’t create private sector jobs,” Mr. Rubio said in the first bilingual response to the President’s speech, in English and then Spanish. “More government isn’t going to help you get ahead,” he added. “It’s going to hold you back.”

“Presidents in both parties — from John F. Kennedy to Ronald Reagan — have known that our free-enterprise economy is the source of our middle-class prosperity. But President Obama? He believes it’s the cause of our problems.”

Kentucky Sen. Rand Paul, in excerpts from a separate Tea Party response, cast blame on both parties, saying “Washington acts in a way that your family never could — they spend money they do not have, they borrow from future generations, and then they blame each other for never fixing the problem.”

Republicans see Mr. Rubio as their bridge to Hispanic voters and to the young. His speech covered Republican themes, including opposition to tax increases and a need to overhaul programs such as the Medicare health-care system for the aged.

“I would never support any changes to Medicare that would hurt seniors like my mother,” Mr. Rubio said. “But anyone who is in favor of leaving Medicare exactly the way it is right now, is in favor of bankrupting it.”

Tuesday’s speech was a high-risk, potentially high-reward mission for the 41-year-old son of Cuban immigrants, the second-youngest Republican in the chamber.

Viewed by many of his Senate colleagues as a rising star in the Republican Party, Mr. Rubio is one of three Hispanics in the chamber. Republicans say he’s well-positioned to help the party woo Latino voters, 71 percent of whom backed President Obama in November.

Mr. Rubio said his parents aren’t millionaires and that they came to the United States “because they were stuck in poverty in countries where the government dominated the economy.”

“So Mr. President, I don’t oppose your plans because I want to protect the rich,” the senator said. “I oppose your plans because I want to protect my neighbors.”

Elected in 2010 with backing from the anti-tax Tea Party, Mr. Rubio has cultivated a more moderate image over the last two years. He’s a leader of a bipartisan Senate effort to rewrite U.S. immigration laws, one of Mr. Obama’s second-term priorities.

“We need a responsible, permanent solution to the problem of those who are here illegally,” Mr. Rubio said. “But first, we must follow through on the broken promises of the past to secure our borders and enforce our laws.”

Mr. Paul urged members of his party to see immigrants “as assets, not liabilities.”

He said the party had a history of embracing “hard work and ingenuity” and that meant Republicans must embrace “the immigrant who wants to come to America for a better future.”

“We must be the party that says, ‘If you want to work, if you want to become an American, we welcome you,’” Mr. Paul said.

Earlier Tuesday, Mr. Rubio drew criticism from women’s groups, another constituency that mostly supported the President, for being one of 22 Republicans who voted against legislation reauthorizing the Violence Against Women Act. The measure would provide government programs and aid to victims. The Senate passed the bill 78-22

The Feb. 18 cover of Time magazine features Mr. Rubio and the headline “The Republican Savior,” prompting Mr. Rubio to post on Twitter, “There is only one savior, and it is not me. #Jesus.”